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Biomedical subjects

J McNeal

Publications and source records attributed to J McNeal.

8 recordsLinked to original sources
PubMed1996

Limitations of transition zone needle biopsy findings in the prediction of transition zone cancer and tissue composition of benign nodular hyperplasia.

OBJECTIVES: The transition zone of the prostate is the origin of 30% of all prostate cancers and of almost all benign prostatic hyperplasia (BPH). We compared histologic findings in transition-zone biopsies to tissue composition of the transition zone from radical prostatectomy specimens from the same patients to determine the efficacy of needle biopsies to evaluate either cancer or BPH. METHODS: A quantitative evaluation of the transition zone for both cancer and BPH in 21 retrospective and 11 prospective radical prostatectomy specimens was made. All retrospective cases had transition-zone biopsies prior to radical prostatectomy; all prospective specimen transition zones were biopsied after surgical removal with an ink-filled needle to trace the needle tracks after specimen processing. For all 32 specimens, total prostate weight, width of transition zone, transition-zone tissue composition, and epithelial/stromal (E/S) ratio of nodular and internodular BPH tissue were noted; the corresponding biopsies were evaluated for the amount of cancer and the composition of nodular and internodular tissue. RESULTS: Eight carcinomas larger than 5.0 cc were detected at biopsy, whereas 5 cancers smaller than 2.0 cc were undetected. Biopsies did not reliably predict BPH tissue composition or epithelial density of prostatectomy specimens; both were markedly underestimated. Dyed needle tracts showed selective sampling of internodular tissue versus nodules by biopsy as an explanation for low correlations. CONCLUSIONS: Transition-zone needle biopsies efficiently detect cancers larger than 5.0 cc and miss cancers smaller than 2.0 cc. Biopsies do not reliably predict BPH tissue composition because of selective sampling of the internodular tissue.

Biopsy, Needle↗
PubMed1993

Gadolinium-enhanced MRI of the abnormal prostate.

A prospective study of the use of a low osmolar gadolinium-based intravenous contrast material for MRI of the abnormal prostate was performed. Eight patients scheduled for prostatectomy, six with prostate cancer and two with benign prostatic hyperplasia (BPH), were imaged preoperatively on a 1.5 T system using a pelvic coil array and employing Gadodiamide (0.3 mmol/kg). T2-weighted fast-spin echo (FSE) imaging was also performed in the same axial planes employed for gadolinium-enhanced studies. Detailed pathologic correlation was performed for the six patients with carcinoma. While regions of BPH and cancer enhanced to a similar degree following intravenous contrast agent, BPH enhancement was more heterogeneous than cancer. No advantages in detecting prostate cancer, in differentiating cancer from BPH or normal prostatic tissue, or in assessing extra-prostatic spread of cancer were observed for the contrast-enhanced studies compared to T2-weighted FSE imaging.

Aged↗
PubMed1993

Determining the volume of prostatic carcinoma: value of MR imaging with an external-array coil.

OBJECTIVE: The size of prostatic carcinomas, as determined by estimations of the tumor volume, has a direct correlation with the histologic grade and stage. Therefore, accurate information about tumor volume can play an important role in determining appropriate treatment and establishing a patient's prognosis. Accordingly, we performed a study to assess the accuracy of MR imaging with external-array coils and the fast spin-echo technique for determining tumor volume in patients with prostatic cancer. SUBJECTS AND METHODS: In a prospective study, 20 patients with biopsy-proved prostatic cancer had MR imaging before radical prostatectomy. A 1.5-T system, a prototype external-array coil, and fast spin-echo technique were used to obtain axial T2-weighted (4000/120 [TR/TE]) MR images throughout the prostate and seminal vesicles. Contiguous 5-mm sections were obtained with a 256 x 256 or 256 x 192 matrix, 24-cm field of view, four excitations, and fat suppression. The volumes of cancer obtained with MR imaging and surgical specimens were determined independently. The areas of tumor were determined from individual axial sections by summing and multiplying by the section thickness. RESULTS: Seventeen of the 20 cancers were detected on MR images. A significant correlation between the volume of the tumor as determined with MR imaging and measurements of the specimens was observed (r = .81, p < .001). Four transition zone tumors were detected as zones of rather homogeneous decreased intensity. One important source of error for volumes determined with MR images was a limitation in the histologic specificity of MR imaging for the delineation of cancer; in some cases benign changes or normal prostates were interpreted as cancer. Another limitation was the presence of changes after biopsy that concealed portions of 10 of the 17 tumors visualized. CONCLUSION: The accuracy of the MR technique used was not sufficient for reliable prediction of tumor volume. The lack of specificity of T2-weighted MR imaging for cancer detection and the presence of changes caused by biopsy were major sources of error.

Aged↗
PubMed1990

DNA content in prostatic adenocarcinoma. A flow cytometry study of the predictive value of aneuploidy for tumor volume, percentage Gleason grade 4 and 5, and lymph node metastases.

DNA content of prostatic adenocarcinoma was determined by flow cytometry on formalin-fixed, paraffin-embedded tissue from 57 radical prostatectomies. This was done to define the relationship of aneuploidy to prostatic adenocarcinoma grade, volume, and pathologic stage and to examine its utility in candidates for surgical treatment. Aneuploidy was found in 26 (46%) cases. With one exception, all of the aneuploid cases were found in tumors larger than 4 cc. The percentage of aneuploid cases increased with advancing pathologic stage, and it was highest in those cases with lymph node metastases. This percentage was also higher among more poorly differentiated tumors. However, diploid tumors were also found among these groups, and the relationship between aneuploidy versus pathologic stage and grade did not achieve statistical significance. Except for a 91% specificity for tumor volume greater than 4 cc, the sensitivity and specificity of DNA content analysis to predict these groups was low (50% to 72%). It is concluded that aneuploidy is a later event linked to tumor progression, but it is not a requirement for progression to occur. The overlap in aneuploid and diploid tumor behavior precludes the use of DNA content analysis as an independent predictor to direct preoperative treatment of prostatic carcinoma.

Adenocarcinoma↗
PubMed1990

Pathology of benign prostatic hyperplasia. Insight into etiology.

Morphometric studies of prostates with benign hyperplasia (BPH) have revealed features that may help clarify the disease's natural history and biologic behavior. Hyperplasia arises within a small anatomic region having precise boundaries and containing an unusual juxtaposition of glandular and stromal elements. Diffuse non-nodular enlargement of the transition zone is the commonest morphologic feature of BPH, but nodules show a greater potential for growth and comprise most of the tissue in large (more than 50-gm) resection specimens. Most nodules are predominantly glandular, with features that suggest a pathogenetic role of induction of embryonic-type stroma.

Animals↗
PubMed1988

Noise-reduced prostatic MR imaging. Work in progress.

Measurement-dependent filtering, a nonlinear noise-reduction technique, was used to improve the signal-to-noise ratio of in vivo T2-weighted magnetic resonance images of the prostate gland. In both normal and abnormal prostates, the technique considerably reduced noise in T2-weighted images. The technique may provide more accurate depiction of regions of benign prostatic hyperplasia and carcinoma in the prostate.

Filtration↗
PubMed1978

Determination of fluoride in deboned meat.

A rapid analytical procedure was investigated for measuring the fluoride content of deboned meat, using a specific ion electrode. The method involves a defatting procedure followed by chelation with EDTA before final solubilization and measurement. Fluoride content is determined by comparison to a standard curve on 2-cycle semi-logarithmic graph paper of fluoride ion vs. millivolt readings. The method is applicable to hand and mechanically deboned pork, beef, and poultry within a range of from 0.7 to 25.0 ppm fluoride. Higher concentrations may be measured by analyzing additional standards and extending the curve into a third cycle. The curve is not linear below 0.7 ppm. Samples less than 0.7 ppm may be estimated by extrapolation. Studies with fortified samples indicate average recoveries of 92 +/- 4.2%. The standard deviation of duplicates within the laboratory is 0.5 ppm in the range stated above.

Animals↗